Express 1/2 Ton Van V8-5.7L VIN R (1999)
Starter Motor: Description and Operation
Two different starter motors are used on these engines.
The PG-260 achieves gear reduction at a ratio of 5:1 through planetary gears. It's relatively small size and light weight and offers improved
cranking performance and reduced current requirements for the gasoline engines. Two versions of the PG-260 are used. The PG-260F2 is used on
the 4.3L and 5.0L, it can be identified by the white ground wire at the starter solenoid. The PG-260M is used on the 5.7L and 7.4L, it can be
identified by the black ground wire at the starter solenoid and has external through bolts.
The 28-MT, used on the 6.5L diesel engine, is a gear reduction starter with an over running roller type clutch and enclosed shift lever. Enclosed
shift lever cranking motors have the shift lever mechanism and the solenoid plunger enclosed in the drive housing, protecting them from exposure
to dirt, icing conditions, and splash.
Solenoid windings are energized when the ignition switch or engine control switch is in the start position. The resulting plunger and shift lever
movement causes the pinion to engage the engine flywheel ring gear, the solenoid main contacts to close, and cranking takes place. When the
engine starts, the pinion over running clutch protects the armature from excessive speed until the ignition switch or engine control switch is
released, at that time the plunger return spring causes the pinion to disengage. To prevent excessive overrunning, release the ignition switch or
engine control switch from the crank position as soon as the engine starts.
